JP2761498B2 - Method of manufacturing expansion sleeve for fastening fastener - Google Patents

Description

Description: The present invention relates to a clamping fastener which extends on the back side of a member, in particular a head at a base end and a nut at a tip end and an axial direction between them. The present invention relates to a method for manufacturing an expansion sleeve of a fastening fastener, which comprises a combination of an expansion sleeve having a plurality of grooves extending to the expansion sleeve and a threaded rod inserted into the expansion sleeve from the proximal end and screwed on a nut.

(Prior art) When fixing building materials and equipment, there has been proposed a fixing tool that can be installed only from the front side without an operator entering into the back side of the member or inserting tools. I have.

An extension sleeve having a head at the proximal end, a nut at the distal end, and a plurality of grooves extending therebetween in the axial direction, and a screw inserted into the extension sleeve from the proximal end and screwed onto the nut Tightening fasteners consisting of a combination with a rod are also one of them.They are inserted into the lower hole of the member to protrude the expanded portion between the grooves and the nut to the back side so that the expansion sleeve does not rotate. By rotating the screw rod while fixing the head, the nut is moved in the proximal direction, the expanded part is bent outward and expanded in the shape of a petal, cooperates with the head and the members are clamped and tightened (For example, Japanese Utility Model Publication No. 29-3006, 56-48)
965).

The expansion sleeve generally has the shape shown in FIG. 16, and a round bar of material is cut to a predetermined length to form a square head 101 at one end by forging, and then a drilled through hole 102 is formed. A female screw 103 is provided at the tip of the through hole 102 by threading to form a nut 104, and a plurality of grooves 105 extending in the axial direction are formed by cutting in a portion between the head 101 and the nut 104. Expand the part between them 106
Is configured.

In other words, since several completely different types of machining must be performed, the process is complicated and complicated,
In particular, when forming the through-hole 102, a large amount of cutting chips are generated, so that a large amount of material is wasted.

(Problem to be Solved by the Invention) The present invention is intended to solve the problem that the conventional method for manufacturing an expansion sleeve involves complicated steps and complicated processing, and also wastes a lot of material. It is an object of the present invention to provide a manufacturing method which is simple and easy to process and hardly causes waste of materials.

(Means for Solving the Problems) In order to solve the above problems, the present invention firstly provides a plurality of grooves radially by cutting a flat plate of material, and secondly, the outer peripheral edge portion of the flat plate by deep drawing. And forming the tip into a small diameter by redrawing, and thirdly, removing the bottom of the tip by punching and forming a female screw on the inner surface of the small diameter tip by threading. Taken.

The flat plate made of a material used in the present invention is made of a metal such as mild steel or stainless steel, which can be deep drawn and has mechanical strength as a fastening fixture. In addition, the head of the expansion sleeve is not only used to hold the member in place but also used as a detent when turning the screw rod to bend and bulge the expanded part. A regular polygon such as a regular hexagon corresponding to the head may be used, but a circular one may be used.

The grooves are radially spaced at equal intervals in the circumferential direction except for the outer peripheral portion, which is the portion where the pilot hole of the head and member is fitted, and the small-diameter distal portion and the central portion, which is the shorter portion on the proximal side. A plurality of cutters are provided, and are formed by cutting with a knife-like cutting tool. Therefore, the groove is linear and provided without generating cutting chips, and a portion between them becomes an enlarged portion.

Next, deep drawing is performed using a well-known device equipped with a die and a punch.In addition to narrowing down to the required depth at once, repeating the operation of gradually narrowing down gradually using a small diameter punch several times It can be performed by finally narrowing down to a necessary depth by re-drawing. Also, re-drawing to form a small-diameter tip portion is performed by using a well-known device equipped with a die and a punch. In this case, too, a step of sequentially adjusting to a predetermined shape by using punches having different diameters and tip shapes. May be applied.

When deep drawing or redrawing is completed, bend the outer peripheral edge of the flat plate to be the head and shape it to the required shape. The die is shaped into a required regular polygon at an arbitrary time, such as forming a die or punch so as to have a predetermined shape when the tip small diameter portion is formed.

Further, the bottom of the tip is removed by shear punching using well known equipment with dies and punches, and material waste is substantially only the bottom portion. Further, the female screw is usually formed by cutting with a tap, but if formed by rolling, it is advantageous since no cutting chips are generated.

In addition, if it is necessary to make the thickness of the expansion sleeve uniform, ironing in a separate step is not prevented. Finally, plating or coating for rust prevention may be applied to the surface.

(Effect) A radial groove is formed in a flat plate by cutting, and a portion between them is formed as an enlarged portion, and then a deep drawing is performed to form a cylindrical body leaving an outer peripheral portion serving as a head. By this step, the grooves are formed in the cylinder so as to extend in the axial direction in parallel with each other, and the bottom of the small-diameter distal end formed by re-drawing is punched to form a female screw to form a nut.

Grooves can be formed all at once from one direction, and the processing of the small-diameter tip and the bottom that forms the cylinder and nut that forms the expanding portion that bends and bulges, and the removal of the bottom and the processing of the female screw are all plastic. The steps performed by the processing means are simple.

(Embodiment) An embodiment of the present invention will be described with reference to the drawings.

First, a circular flat plate 1 made of mild steel or stainless steel having a required thickness and diameter is prepared, and six grooves 2 are cut at regular intervals in the circumferential direction except for the outer peripheral edge and the center. (Fig. 1). The groove 2 is formed by placing the flat plate 1 on a table, and simultaneously cutting six knife-shaped cutting tools from above, and moving the cutting tools simultaneously or sequentially in the radial direction as necessary to form a linear shape. It is formed.

Second, deep drawing by re-drawing is performed using the apparatus shown in FIGS. That is, the die of the apparatus shown in FIG.
The flat plate 1 provided with the groove 2 is placed on 21 and the outer peripheral portion thereof is pressed down with a wrinkle presser 24, and the punch 23 is driven to push the entire flat plate 1 into the gap between the die hole 22 and the punch 23, thereby forming a bottom. (FIG. 2). Next, the first cylinder 3 is placed concentrically with the die hole 26 on the die 25 of the apparatus shown in FIG. 11, and the punch 27 is driven. Of the opening of the die hole 26 and the inclined shoulder 27a of the punch 27.
To form an oblique flange 5 extending outward and upward (FIG. 3). Further, the punch 30 is driven by placing the second cylindrical body 4 on the die 28 of the apparatus shown in FIG. 12 concentrically with the die hole 29a, and the third cylindrical body 4 has a smaller diameter than the second cylindrical body 4 and is deeply squeezed. A cylindrical body 6 is formed, and a right-angled flange 7 is formed between the right-angled shoulder 30a of the punch 30 and the upper surface of the die 28 with the oblique flange 5 interposed therebetween.
Is formed (FIG. 4).

When the above deep drawing is completed, redrawing for forming a small diameter tip portion is performed using the apparatus shown in FIGS. That is, the punch 33 is driven by placing the third cylindrical body 6 on the die 31 of the apparatus shown in FIG. 13 concentrically with the die hole 32,
A fourth cylinder 8 having a diameter smaller than that of the third cylinder 6 and being deeply squeezed is formed, and a small diameter hole 32A at the bottom of the die hole 32 and a small diameter portion 33a at the tip of the punch 33 are used to form the cylinder 8. Tip 9
To a small diameter (FIG. 5). Further, the fourth cylinder 8 is placed on the die 34 of the apparatus shown in FIG. 14 concentrically with the die hole 35 and the punch 36 is driven, and the cylinder 8 and the tip 9 are squeezed to form a fifth cylinder 5 having a predetermined size. While finishing the body 10 and its tip 11,
The head 12 having a regular hexagon with a right-angled flange 7 interposed between the entrance of the die hole 35, the rising edge 35a, and the downward groove 36a of the step of the punch 36 is formed having a downwardly projecting edge 12a on the outer peripheral edge (sixth). Figure).

Third, a female screw is formed on the inner surface of the small-diameter distal end portion 11 by removing the bottom of the distal end. That is, the fifth cylindrical body 10 and the tip 11 are fitted into the die hole 38 of the die 37 of the apparatus shown in FIG. 15, the punch 39 is driven, and the bottom is removed by punching by shearing (FIG. 7). . Then, the female screw 14 is formed on the inner surface of the distal end portion 11 by cutting or rolling.

FIGS. 8 and 9 show the expansion sleeve made by the above-described process, and the portion corresponding to the fifth cylindrical body 10 extends in the axial direction over substantially the entire length except for the portion fitted into the lower hole of the member. The six extending grooves 2 extend in parallel with each other at equal intervals in the circumferential direction, and a portion therebetween forms an enlarged portion 13. The small-diameter tip 11 provided with the female screw 14 is
Is formed.

In addition, this expansion sleeve is inserted from the front side into a prepared hole provided in, for example, two or more plate-like members stacked in a state where a threaded rod is inserted from the base end side and screwed into the nut 15, and the head 12 is attached. By turning the screw rod while fixing it so that it does not turn, the nut
15 is moved in the proximal direction, the expanding portion 13 projecting to the back side of the member is bent at the middle portion, swelled outward and expanded like a petal, and cooperates with the head 12 to pinch and tighten the member The usage and function are the same as those of the conventional product.

(Effects of the Invention) According to the present invention, a cylindrical body forming a petal-shaped expanding portion and a small-diameter tip portion forming a nut are formed by deep drawing using a flat plate as a material, and grooves are provided by cutting. As such, there is the advantage that there is no waste of material except for the bottom to be removed. In addition, the processing of the cylindrical body and the small diameter tip, the removal of the bottom, the formation of internal threads, and the shaping of the head to be performed as necessary are all performed by plastic working means, so that the process is simple and the processing is simple, and the cost is low. Suitable for mass production.

[Brief description of the drawings]

1 to 7 are explanatory views showing an example of a molding process of the expansion sleeve of the present invention, FIG. 8 is a front view of a partially cut product, FIG. 9 is a bottom view of FIG. FIG. 15 to FIG.
Sectional partial views of the apparatus corresponding to the molding process of FIGS.
FIG. 16 is a longitudinal sectional view of a conventional expansion sleeve. DESCRIPTION OF SYMBOLS 1 ... Flat plate, 2 ... Groove, 3, 4, 6, 8, 10 ... Cylindrical body, 9, 11 ... Tip part, 12 ... Head part, 13 ... Expanding part, 14
...... Female thread, 21, 25, 28, 31, 34, 37 ... Dice, 23,
27, 30, 33, 36, 39 ... punch

Claims (1)

(57) [Claims] 1. First, a plurality of grooves are radially provided in a flat plate of a material by cutting, and second, the flat plate is processed into a cylindrical body with a bottom by deep drawing while leaving an outer peripheral portion, and a tip portion is formed. Manufacturing an expansion sleeve of a fastening fastener, characterized in that it is formed into a small diameter by redrawing, and thirdly, a bottom of the tip is removed by punching and a female screw is formed on the inner surface of the small diameter tip by threading. Method.